| rabbit |
a small plug that is run through a
flow line by pressure to clean the line or test for obstructions (see pig). |
| racking
platform |
a small platform with finger-like
steel projections attached to the side of the mast on a well servicing unit. When a
string of sucker rods or tubing is pulled from a well, the top end of the rods or tubing
is placed (racked) between the steel projections and held in a vertical position in the
mast. |
| rack pipe |
1. to place pipe withdrawn from
the hole on a pipe rack 2. to stand pipe on
the derrick floor when pulling it out of the hole. |
| RAD |
abbreviation: radioactive
densiometer; fluid-measuring device to measure density. |
| radical |
two or more atoms behaving as a
single chemical unit, i.e., as an atom, e.g., sulfate, phosphate, nitrate. |
| radioactivity well logging |
the recording of the natural or
induced radioactive characteristics of subsurface formations. A radioactivity log,
also known as a radiation log or a nuclear log, normally consists of two recorded curves:
a gamma ray curve and a neutron curve. Both help to determine the types of rocks in
the formation and the types of fluids contained in the rocks. |
| ram |
the closing and sealing component
on a blowout preventer. One of three types--blind, pipe, or shear--may be installed
in several preventers mounted in a stack on top of the wellbore. Blind rams, when
closed, form a seal on a hole that has no drill pipe in it; pipe rams, when closed, seal
around the pipe; shear rams cut through drill pipe and then form a seal. |
| ram
blowout preventer |
a blowout preventer that uses rams
to seal off pressure on a hole that is with or without pipe. Also called a ram preventer. |
| ram
preventer |
see ram blowout preventer. |
| range of
load |
in sucker rod pumping, the
difference between the polished rod peak load on the upstroke and the minimum load on
the downstroke. |
| ratchet |
a generic term used to describe
certain tool movements, such as the cone-to-slip engagement on permanent packers or plugs. |
| rate of penetration (ROP) |
a measure of the speed at which
the bit drills into formations, usually expressed in feet (meters) per hour or minutes per
foot (meter). |
| rate of
shear |
rate (commonly given in rpm) at
which an action resulting from applied forces causes or tends to cause two adjacent parts
of a body to slide relative to each other in a direction parallel to their plane of
contact. |
| rathole |
1. a hole in the rig floor, 30 to
35 feet (9 to 11 meters) deep, which is lined with casing that projects above the floor
and into which the kelly and swivel are placed when hoisting operations are in progress.
2. a hole of a diameter smaller than the main
hole and drilled in the bottom of the main hole.
v: to reduce the size of the wellbore and drill ahead. |
| ream |
to enlarge the wellbore by
drilling it again with a special bit. Often a rathole is reamed or opened to the
same size as the main wellbore. See rathole. |
| reamer |
a tool used in drilling to smooth
the wall of a well, enlarge the hole to the specified size, help stabilize the bit,
straighten the wellbore if kinks or doglegs are encountered, and rill directionally.
See ream. |
| reciprocating
pump |
a pump consisting of a piston that
moves back and forth or up and down in a cylinder. The cylinder is equipped with
inlet (suction) and outlet (discharge) valves. On the intake stroke, the suction
valves are opened, and fluid is drawn into the cylinder. On the discharge stroke,
the suction valves close, the discharge valves open, and fluid is forced out of the
cylinder. |
| recompletion |
after the initial completion of a
well, the action and techniques of reentering the well and redoing or repairing the
original completion to restore the well's productivity. |
| recorder
carrier |
a sub in a DST string in which
pressure and temperature recorders are placed for formation evaluation. |
| recovery
efficiency |
the recoverable amount of original
or residual hydrocarbons in place in a rese4rvoir, expressed as a percentage of total
hydrocarbons in place. Also called recovery
factor. |
| recovery
factor |
see recovery
efficiency |
| red-lime
mud |
a water-base clay mud containing
caustic soda and tannates to which lime has been added. Also called red mud. |
| red mud |
see red-lime
mud. |
| reeled
tubing |
lighter-duty well maintenance than
hydraulic workover, employing small OD tubing capable of descending down the production
string under well pressure |
| reel vessel |
a ship or barge specially designed
to handle pipeline that is wound onto a large reel. To lay the pipeline, the vessel
pays out the pipe off the reel at a steady rate onto the ocean flow. The pipeline
has been constructed at an offshore facility where it has been welded, coated, inspected,
and wound onto the reel. |
| reeve |
to pass (as a rope) through a hole
or opening in a block or similar device. |
| reeve the
line |
to string a wire rope drilling
line through the sheaves of the traveling and crown blocks to the hoisting drum. |
| refracturing |
fracturing a formation again.
See formation fracturing,
hydraulic fracturing. |
| regulator |
a device that reduces the pressure
or volume of a fluid flowing in a line and maintains the pressure or volume at a specified
level. |
| relative
density |
1. the ratio of the weight of a
given volume of a substance at a given temperature to the weight of an equal volume of a
standard substance at the same temperature. For example, if 1 cubic inch of water at 39
degrees F weighs 1 unit and 1 cubic inch of another solid or liquid at 39 degrees F weight
0.95 unit, then the relative density of the substance is 0.95. In determining the relative
density of gases, the comparison is made with the standard of air or hydrogen. 2. the ratio of the mass of a given volume of a substance to the
mass of a like volume of a standard substance, such as water or air. |
| relative
permeability |
the radio of effective
permeability to absolute permeability. The relative permeability of rock to a single
fluid is 1.0 when only that fluid is present, and 0.0 when the presence of another fluid
prevents all flow of the given fluid. Compare absolute permeability, effective
permeability. |
| relief
valve |
a valve that will open
automatically when pressure gets too high. |
| relief well |
a well drilled near and deflected
into a well that is out of control, making it possible to bring the wild well under
control. See wild well. |
| remote
choke panel |
a set of controls, usually placed
on the rig floor, that is manipulated to control the amount of drilling fluid being
circulated through the choke manifold. This procedure is necessary when a kick is
being circulated out of a well. See choke manifold. |
| remote (secondary) control panel |
a system of controls, convenient
to the driller, which can be used selectively to actuate valves at the master control
panel. |
| remote
control station |
a station containing equipment to
control and regulate operations in the field. |
| replacement |
the process whereby a volume of
fluid equal to the volume of steel in tubular and tools withdrawn from the wellbore is
returned to the wellbore. |
| reservoir |
a porous and permeable underground
formation containing an individual and separate natural accumulation of producible
hydrocarbons (oil and/or gas) which is confined by impermeable rock or water barriers and
is characterized by a single natural pressure system. A subsurface, porous, permeable rock
body in which oil and/or gas is stored, Most reservoir rocks are limestones, dolomites,
sandstones, or a combination of these. The three basic types of hydrocarbon
reservoirs are oil, gas, and condensate. An oil reservoir generally contains three
fluids - gas, oil, and water - with oil the dominant product. In the typical oil
reservoir, these fluids occur in different phases because of the variance in their
gravities. Gas, the lightest, occupies the upper part of the reservoir rocks; water, the
lower part; and oil, the intermediate section. In addition to its occurrence as a cap or
in solution, gas may accumulate independently of the oil; if so, the reservoir is called a
gas reservoir. Associated with the gas, in most instances, are salt water and some
oil. In a condensate reservoir, the hydrocarbons may exist as a gas, but, when
brought to the surface, some of the heavier ones condense to a liquid. |
| reservoir drive mechanism |
the process in which reservoir
fluids are caused to flow out of the reservoir rock and into a wellbore by natural
energy. Gas drives depend on the fact that, as the reservoir is produced, pressure
is reduced, allowing the gas to expand and provide the driving energy. Water-drive
reservoirs depend on water pressure to force the hydrocarbons out of the reservoir and
into the wellbore. |
| reservoir
pressure |
the average pressure within the
reservoir at any given time. Determination of this value is best made by bottomhole
pressure measurements with adequate shut-in time. If a shut-in period long enough
for the reservoir pressure to stabilize is impractical, then various techniques of
analysis by pressure buildup or drawdown tests are available to determine static reservoir
pressure. |
| reservoir
rock |
a permeable rock that may contain
oil or gas in appreciable quantity and through which petroleum may migrate. |
| resin |
semisolid or solid complex,
amorphous mixture of organic compounds having no definite melting point or tendency to
crystallize. Resins may be a component of compounded materials that can be added to
drilling fluids to impart special properties to the system, to wall cake, etc. |
| resistivity |
the electrical resistance offered
to the passage of current; the opposite of conductivity. |
| resistivity
meter |
an instrument for measuring the
resistivity of drilling fluids and their cakes. |
| retainer |
a cast-iron or magnesium drillable
tool consisting of a packing assembly and a back-pressure valve. It is used to close
off the annular space between tubing or drill pipe and casing to allow the placement of
cement or fluid through the tubing or drill pipe at any predetermined point behind the
casing or liner, around the shoe, or into the open hole around the shoe. |
| retarder |
a substance added to cement to
prolong the setting time so that the cement can be pumped into place. Retarders are
used for cementing in high-temperature formation |
| retrievable wireline choke |
a bottomhole choke run on wireline
and landed in a nipple profile in the tubing string. |
| reverse
circulation |
the course of drilling fluid
downward through the annulus and upward through the drill stem, in contrast to normal
circulation in which the course is downward through the drill stem and upward through the
annulus. Seldom used in open hole, but frequently used in workover operations.
Also referred to as "circulating the short way," since returns from
bottom can be obtained more quickly than in normal circulation. |
| reverse out |
to displace the wellbore fluid
back to the surface; to displace tubing volume back to the pit. |
| reversing
hand |
a well servicing hand who cleans
out wellbores. |
| rheology |
the study of the flow of gases and
liquids of special importance to mud engineers and reservoir engineers. |
